US5046137A - Optical communication system - Google Patents

Optical communication system Download PDF

Info

Publication number
US5046137A
US5046137A US07/469,065 US46906590A US5046137A US 5046137 A US5046137 A US 5046137A US 46906590 A US46906590 A US 46906590A US 5046137 A US5046137 A US 5046137A
Authority
US
United States
Prior art keywords
terminal equipment
signal
terminal
terminal equipments
time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/469,065
Other languages
English (en)
Inventor
Akio Kurobe
Hiromasa Nakatsu
Masao Ikezaki
Nobuo Sugino
Yosihisa Mochida
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: IKEZAKI, MASAO, KUROBE, AKIO, MOCHIDA, YOSIHISA, NAKATSU, HIROMASA, SUGINO, NOBUO
Application granted granted Critical
Publication of US5046137A publication Critical patent/US5046137A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/27—Arrangements for networking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/27—Arrangements for networking
    • H04B10/278—Bus-type networks

Definitions

  • the present invention relates to an optical communication system for realizing a digital data bus for performing information communication between audio and video appliances.
  • FIG. 1 shows an example of a system construction of a digital data bus realized by electric communication using metallic wire as a transmission medium.
  • portions surrounded by broken lines designate terminal equipments which are connected to each other through metallic wire.
  • the reference numeral 3 designates a communication interface section for performing data communication according to a predetermined communication protocol.
  • a driver circuit 1 and a receiver circuit 2 are connected to the communication interface section 3.
  • the reference numerals 15 and 16 designate an input terminal and an output terminal respectively.
  • the output terminal of each terminal equipment is connected to the input terminal of the succeeding terminal equipment through metallic wire successively to thereby constitute a bus-shaped transmission line. Because output signals from the respective terminal equipments can be simultaneously received by all of the terminal equipments through the bus-shaped transmission line, it is possible to perform channel access control based on surviving type CSMA/CD (Carrier Sense Multiple Access with Collision Detection).
  • the reference numeral 17 designates terminal resistors which are provided on opposite ends of the bus for the purpose of impedance matching.
  • each terminal equipment may be constituted by a coupler for coupling a transmission signal with an up-load signal and a branch device for branching a reception signal from a down-load signal by use of optical fiber as a transmission medium to thereby facilitate multiple transmission of audio and video signals as well as digital data and conserving wiring between terminal equipments.
  • a large insertion loss occurs in the branch device as well as in the coupler, so that the levels of signals between terminal equipments vary widely in the case of bus connection.
  • an increase in signal delay time is caused by an opto-electric converter section and an electro-optic converter section, so that there has been a limitation in transmission rate, in number of terminal equipments and in line length for realizing channel access control based on the surviving type CSMA/CD.
  • An object of the invention is to provide an optical communication system for realizing a digital data bus in which the aforementioned problems are solved.
  • the light sending-out level in each terminal equipment is made variable and each terminal equipment measures a packet transmitted by the terminal equipment itself and informs the other terminal equipments of the result of the measurement so that each terminal equipment sets its sending-out level to the largest value of the sending-out levels of which the terminal equipment has been informed.
  • each terminal equipment measures the delay time of an acknowledge bit transmitted from the other terminal equipments so that each terminal equipment shifts a sampling point by the mean value of the measured delay time.
  • bus connection of terminal equipments through optical fiber can be facilitated, and at the same time, channel access control based on the surviving type CSMA/CD can be performed. Furthermore, multiple transmission of audio and video signals as well as digital data and conversation of wiring between terminal equipments can be attained.
  • FIG. 1 is a configuration diagram of a conventional digital data bus
  • FIG. 2 is a configuration diagram showing a first embodiment of the present invention
  • FIG. 3 is a configuration diagram showing a second embodiment of the present invention.
  • FIG. 4 is a diagram for explaining the packet format in a digital data bus
  • FIG. 5 is a diagram for explaining the bit format of an acknowledge bit in a digital data bus
  • FIG. 6 is a diagram for explaining the case where an acknowledge bit is transmitted and received between terminal equipments
  • FIG. 7 is a diagram for explaining the bit format of a mode bit and a master address bit in a digital data bus
  • FIG. 8 is a diagram for explaining the packet format and the byte format in a home-bus system.
  • FIG. 2 is a diagram showing a first embodiment of the optical communication system according to the present invention.
  • the terminal equipments A, B, . . . , D are connected to each other through optical fiber.
  • the terminal equipments A, B, . . . , D correspondingly respectively include: driver circuits 1a, 1b, . . . , 1d; receiver circuits 2a, 2b, . . . , 2d; communication interface sections 3a, 3b, . . . , 3d; electro-optic converter sections 4a, 4b, . . . , 4d; first branch couplers 5a, 5b, . . .
  • each terminal equipment A B, . . . , D
  • the communication interface section 3a (3b, . . . , 3d) operates together with the driver circuit 1a (1b, . . . , 1d) and the receiver circuit 2a (2b, . . . , 2d) to perform transmission/reception of an electric signal in accordance with a predetermined communication protocol.
  • a transmission signal is converted into an optical signal by the electro-optic converter section 4a (4b, . . . , 4d) and a received optical signal is converted into an electric signal by the opto-electric converter section 7a(7a, . . .
  • the transmission signal is coupled with an up-load optical signal inputted from the up-load optical signal input terminal 8a (8b, . . . , 8d) and then sent out from the up-load optical signal output terminal 9a (9b, . . . , 9d).
  • the up-load optical signal output terminal 9d of the terminal equipment D is connected to the up-load optical signal input terminal 8c of the terminal equipment C through optical fiber.
  • the up-load optical signal output terminal 9a of the terminal equipment A is connected to the down-load optical signal input terminal 10a of the terminal equipment A through optical fiber, so that the signals transmitted from all of the terminal equipments are inputted to the down-load optical signal input terminal 10a as a down-load optical signal.
  • a signal inputted through the down-load optical signal input terminal 10a (10b, . . . , 10d) is branched into two by the second branch coupler 6a (6b, . . .
  • the down-load optical signal output terminal 11a of the terminal equipment A is connected to the down-load optical signal input terminal 10b of the terminal equipment B through optical fiber.
  • each terminal equipment A (B, . . . , D) transmits a packet addressed to itself.
  • the gain of the optical amplifier 12a (12b, . . . , 12d) is started from its minimum.
  • the packet addressed to itself is transmitted again after the amplification factor of the optical amplifier 12a (12b, . . . , 12d) is increased by one rank. The aforementioned operation is repeated until reception is enabled.
  • the signal sent out from the optical amplifier 12a (12b, . . . , 12d) in each terminal equipment A (B, . . . , D) is attenuated because of losses such as a branching loss, a coupling loss, an insertion loss, and a transmission loss of optical fiber, and then reaches to a reception point.
  • the signal sent out of the optical amplifier 12a of the terminal equipment A is passed through the branch couplers 5a and 6a.
  • the signal sent out of the optical amplifier 12d of the terminal equipment D is passed through the branch couplers 5d, 5c, 5b, 5a, 6a, 6b, 6c and 6d. Accordingly, in FIG.
  • the amplification factor of the terminal equipment A may be set to be the smallest value and, on the other hand, the amplification factor of the terminal equipment D must be set to be the largest value. In short, data communications between all of the terminal equipments can be made without difficulty if the amplification factors of all the terminal equipments have the same value as the amplification factor of the terminal equipment D.
  • each terminal equipment informs the other terminal equipments of its own amplification factor by means of a broadcast packet, and each terminal equipment sets the amplification factor of its own optical amplifier to be the largest value of the amplification factors received through the broadcast packet.
  • FIG. 3 shows a second embodiment of the optical communication system according to the present invention.
  • the reference numerals 13a, 13b, . . . , 13d designate counting means for counting the time difference between the time when a signal is transmitted from the communication interface section 3a (3b, . . . , 3d) to the driver circuit 1a (1a, . . . , 1d) in the case of packet transmission and the time when an acknowledge bit reaches the communication interface section 3a (3b, . . . , 3d) through the receiver circuit 2a (2b, . . . , 2d), and for reporting the result of the counting to the communication interface section 3a, (3b, . . . , 3d).
  • the reference numerals 14a, 14b, . . . , 14d designate indication means.
  • FIG. 4 shows the data format in a digital data bus.
  • the symbol P in the format represents a parity bit, A an acknowledge bit and EOD an end-of-data bit.
  • the digital data bus is synchronized based on a start bit and then channel access control by CSMA/CD is performed based on mode and master address bits following the start bit. Consequently, one terminal equipment remaining undefeated acquires priority and transmits parity bits, slave address bits, control bits, data bits and an end-of-data bit as a master.
  • An acknowledge bit is the bit for reporting the fact that a terminal equipment designated by the slave address bits has acknowledged information coming to the terminal equipment.
  • the designated terminal equipment transmits with the passage of a predetermined time after the terminal equipment receives a bit synchronizing signal transmitted from the master in the early stage of the period of the respective acknowledge bit.
  • FIG. 5 shows the bit format of the acknowledge bit.
  • the diagram (a) shows a bit synchronizing signal for the acknowledge bit transmitted by the terminal equipment A as a master
  • the diagram (b) shows the state where the bit synchronizing signal of the diagram (a) reaches the output of the receiver circuit 2d of the terminal equipment D as a slave.
  • the signal of the diagram (b) is delayed, compared with the signal of the diagram (a), for the sum T DA-D of the delay time in the driver circuit 1a and the electro-optic converter section 4a of the terminal equipment A, the delay time in the light transmission line leading from the output point of the electro-optic converter section 4a to the input of the opto-electric converter section 7d of the terminal equipment D and the delay time in the opto-electric converter section 7d and the receiver circuit 2d.
  • the acknowledge signal reaches the master in the form of an acknowledge signal shown in the diagram (d) after the signal is delayed for the sum T DD-A of the delay time in the driver circuit 1d and the electro-optic converter section 4d of the terminal equipment D, the delay time in the light transmission line leading from the output point of the electro-optic converter section 4d to the input of the opto-electric converter section 7a of the terminal equipment A and the delay time in the opto-electric converter section 7a and the receiver circuit 2a.
  • the one-cycle transmission delay time between the terminal equipments can be found by counting the time difference T D between the point of time when the master transmits a high-level signal with the passage of time T M after transmitting a bit synchronizing signal and the point of time when the master receives an acknowledge signal from the slave.
  • the terminal equipment to which a transmission request is given transmits a packet after confirming that a vacant channel exists.
  • each terminal equipment transmits mode bits and master address bits synchronously with the terminal equipment which has transmitted the start bit at the first time.
  • Each terminal equipment receives bits and compares the received bits with the bits which the terminal equipment has transmitted. When the result of comparison is discord, the terminal equipment stops signal transmission.
  • the system is configured so that, in the case where a high-level bit and a low-level bit collide with each other, the result is made to be low-level, that is priority is given to the low-level bit. Accordingly, a terminal equipment which has transmitted the mode and master address bits containing the greatest number of low-level bits acquires channel access priority to serve as a master.
  • FIG. 7 The bit format of the mode and master address bits is shown in FIG. 7.
  • the diagram (a) shows the bit format for a terminal equipment to which a transmission request is given and the diagram (b) shows the bit format for a terminal equipment to which no transmission request is given.
  • a terminal equipment to which a transmission request is given transmits a bit data of high- or low-level signal for a time period t 3 with a passage of time t 2 after receiving the bit synchronizing signal which is transmitted with a passage of time t 1 after the start bit of the terminal equipment which has transmitted the start bit at the first time is terminated.
  • Each terminal equipment A (B, . . . , D) performs sampling of the output signal of the receiver circuit 2a (2b, . . .
  • each terminal equipment A (B, . . . , D) contains one driver circuit 1a (1b, . .
  • the delay time is considered to be the same even in the case where a communication is made between arbitrary terminal equipments.
  • the delay time is represented by T DT
  • the one-cycle transmission delay time T D can be represented by the sum of the delay time T DT and the delay time T Do in the optical transmission line.
  • settled data can be sampled regardless of the delay time caused by the driver circuit 1a (1b, . . . , 1d), the receiver circuit 2a (2b, . . . , 2d), the electro-optic converter circuit 4a (4b, . . . , 4d) and the opto-electric converter circuit 7a (7b, . . . , 7d) constituting the terminal equipment A (B, . . . , D) if the delay time caused by the light transmission line is less than the bit length with settled data.
  • the system can be modified as follows, and system reliability can be improved by the modification.
  • the system is designed to report the fact to terminal equipments having delay time T Do more than the bit length t 3 so that signal transmission stops and abnormality is reported to the user by any indication means.
  • the packet format of the home bus system is shown in FIG. 8.
  • the symbol PR in the format represents a priority code, SA a source address, DA a destination address, CC a control code, BC a telegram-length code, DATA data, FCC a check code, DMY a dummy, and ACK/NAK an acknowledge code.
  • the home bus system employs start-stop synchronization in which synchronization is made based on the start bit and the stop bit contained in each byte as a constituent member of a packet.
  • a terminal equipment designated by the destination address DA returns an acknowledge code with the passage of dummy time (time corresponding to 11 bits) after the terminal equipment receives the packet until the check code FCC.
  • the one-cycle transmission delay time T D can be found by subtracting the time corresponding to 11 bits from the value obtained by counting the time difference between the point of time when transmission of the stop bit of the check code is terminated in the terminal equipment to transmit a packet and the point of time when reception of the start bit of the acknowledge code from the other terminal equipment is started.
  • channel access control is made based on the respective bits of the priority code and the source address.
  • start-stop synchronization as in the home bus system regardless of bit synchronization, it generally, sampling is made in the center of the bit with settled data. In the case where pulse duty ratio is 50%, sampling is made in the point of 1/4 bit length of the respective bit.
  • sampling is made in the point of 1/2 bit length of the respective bit.
  • the limit of the one-cycle transmission delay time T D is 1/4 bit time in the case where pulse duty ratio is 50%.
  • the limit of the one-cycle transmission delay time T D is 1/2 bit time in the case where pulse duty ratio is 100%. Accordingly, the scale of the system is limited more as transmission rate increases. According to the method of the invention, sampling timing can be shifted by the mean delay time in the distribution of the transmission delay time through founding the transmission delay time of each terminal equipment according to the method of the invention, so that the permissible range of the one-cycle transmission delay time can be greatly enlarged.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computing Systems (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Small-Scale Networks (AREA)
US07/469,065 1989-01-27 1990-01-23 Optical communication system Expired - Fee Related US5046137A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1-017992 1989-01-27
JP1017992A JPH02199942A (ja) 1989-01-27 1989-01-27 光通信装置

Publications (1)

Publication Number Publication Date
US5046137A true US5046137A (en) 1991-09-03

Family

ID=11959222

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/469,065 Expired - Fee Related US5046137A (en) 1989-01-27 1990-01-23 Optical communication system

Country Status (4)

Country Link
US (1) US5046137A (de)
EP (1) EP0380341B1 (de)
JP (1) JPH02199942A (de)
DE (1) DE69022256T2 (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5109532A (en) * 1990-01-30 1992-04-28 General Instrument Corporation Elimination of phase noise and drift incident to up and down conversion in a broadcast communication system
DE4139300A1 (de) * 1991-11-29 1993-06-03 Rheydt Kabelwerk Ag Netzwerk-topologie zur datenuebertragung
US5809187A (en) * 1997-04-24 1998-09-15 Boeing North American, Inc. Multi-port network using passive optical couplers
US20030053166A1 (en) * 2001-09-14 2003-03-20 Hamm Russell O. Method and apparatus of transmitting several digital signals over a common optical fiber
US20040062474A1 (en) * 2002-09-27 2004-04-01 Whittaker G. Allan Optical interface devices having balanced amplification
US6721838B1 (en) * 1999-11-15 2004-04-13 Samsung Electronics Co., Ltd. Apparatus and method for bus interface for matching optical module
US7085497B2 (en) 2002-04-03 2006-08-01 Lockheed Martin Corporation Vehicular communication system
US7283480B1 (en) 2002-11-12 2007-10-16 Lockheed Martin Corporation Network system health monitoring using cantor set signals
US7349629B1 (en) 2002-11-26 2008-03-25 Lockheed Martin Corporation Methods and systems for creating a digital interconnect fabric
US7424228B1 (en) 2003-03-31 2008-09-09 Lockheed Martin Corporation High dynamic range radio frequency to optical link
US7440699B1 (en) 2004-06-28 2008-10-21 Lockheed Martin Corporation Systems, devices and methods for transmitting and receiving signals on an optical network
US7570887B2 (en) 2003-03-31 2009-08-04 Lockheed Martin Corporation Optical network interface systems and devices
USRE41247E1 (en) 1997-04-01 2010-04-20 Lockheed Martin Corporation Optical transport system
CN103378905A (zh) * 2012-04-27 2013-10-30 鸿富锦精密工业（深圳）有限公司 光纤传输***
CN103457662A (zh) * 2012-05-28 2013-12-18 鸿富锦精密工业（深圳）有限公司 光纤传输***

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0671266B2 (ja) * 1990-06-01 1994-09-07 日本航空電子工業株式会社 光トランシーバ
US20040076434A1 (en) * 2002-09-27 2004-04-22 Whittaker G. Allan Optical distribution network for RF and other analog signals
WO2009022672A1 (ja) * 2007-08-10 2009-02-19 Nec Corporation 光データバス及びこれを用いた光データ伝送システム
JP2011049964A (ja) * 2009-08-28 2011-03-10 Denso Corp 通信システムに用いられるノード
CN112861364B (zh) * 2021-02-23 2022-08-26 哈尔滨工业大学（威海） 一种基于状态时延转换图二次标注的工控***设备行为建模实现异常检测的方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5857835A (ja) * 1981-09-30 1983-04-06 Yokogawa Hokushin Electric Corp 光通信方式
US4742576A (en) * 1985-12-23 1988-05-03 Polaroid Corporation Optical communication system employing coherent detection and method
US4809361A (en) * 1985-11-13 1989-02-28 Fujitsu Limited Optical composite transceiver

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60501286A (ja) * 1983-05-12 1985-08-08 アメリカン テレフオン アンド テレグラフ カムパニ− 通信ネットワ−ク
EP0216214B1 (de) * 1985-09-25 1991-05-08 Siemens Aktiengesellschaft Verfahren zum automatischen Pegelabgleich in einem lokalen Netz, insbesondere für eine Mehrrechneranordnung, mit einem Bussystem mit Lichtwellenleitern, zum Zwecke einer Kollisionserkennung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5857835A (ja) * 1981-09-30 1983-04-06 Yokogawa Hokushin Electric Corp 光通信方式
US4809361A (en) * 1985-11-13 1989-02-28 Fujitsu Limited Optical composite transceiver
US4742576A (en) * 1985-12-23 1988-05-03 Polaroid Corporation Optical communication system employing coherent detection and method

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5109532A (en) * 1990-01-30 1992-04-28 General Instrument Corporation Elimination of phase noise and drift incident to up and down conversion in a broadcast communication system
DE4139300A1 (de) * 1991-11-29 1993-06-03 Rheydt Kabelwerk Ag Netzwerk-topologie zur datenuebertragung
USRE41247E1 (en) 1997-04-01 2010-04-20 Lockheed Martin Corporation Optical transport system
US5809187A (en) * 1997-04-24 1998-09-15 Boeing North American, Inc. Multi-port network using passive optical couplers
US6721838B1 (en) * 1999-11-15 2004-04-13 Samsung Electronics Co., Ltd. Apparatus and method for bus interface for matching optical module
US20030053166A1 (en) * 2001-09-14 2003-03-20 Hamm Russell O. Method and apparatus of transmitting several digital signals over a common optical fiber
US7085497B2 (en) 2002-04-03 2006-08-01 Lockheed Martin Corporation Vehicular communication system
USRE40425E1 (en) 2002-09-27 2008-07-08 Lockheed Martin Corporation Optical interface devices having balanced amplification
US20040062474A1 (en) * 2002-09-27 2004-04-01 Whittaker G. Allan Optical interface devices having balanced amplification
US6912339B2 (en) 2002-09-27 2005-06-28 Lockheed Martin Corporation Optical interface devices having balanced amplification
US7283480B1 (en) 2002-11-12 2007-10-16 Lockheed Martin Corporation Network system health monitoring using cantor set signals
US7349629B1 (en) 2002-11-26 2008-03-25 Lockheed Martin Corporation Methods and systems for creating a digital interconnect fabric
US7424228B1 (en) 2003-03-31 2008-09-09 Lockheed Martin Corporation High dynamic range radio frequency to optical link
US7570887B2 (en) 2003-03-31 2009-08-04 Lockheed Martin Corporation Optical network interface systems and devices
US7440699B1 (en) 2004-06-28 2008-10-21 Lockheed Martin Corporation Systems, devices and methods for transmitting and receiving signals on an optical network
CN103378905A (zh) * 2012-04-27 2013-10-30 鸿富锦精密工业（深圳）有限公司 光纤传输***
CN103378905B (zh) * 2012-04-27 2017-02-08 鸿富锦精密工业（深圳）有限公司 光纤传输***
CN103457662A (zh) * 2012-05-28 2013-12-18 鸿富锦精密工业（深圳）有限公司 光纤传输***

Also Published As

Publication number Publication date
DE69022256D1 (de) 1995-10-19
EP0380341A3 (de) 1991-10-02
JPH02199942A (ja) 1990-08-08
DE69022256T2 (de) 1996-05-09
EP0380341A2 (de) 1990-08-01
EP0380341B1 (de) 1995-09-13

Similar Documents

Publication Publication Date Title
US5046137A (en) Optical communication system
CA1275699C (en) Dual media local area network interfacing
EP0110691B1 (de) System und Verfahren zur Steuerung eines Datenfernmeldesystems mit Vielfachzugriff
US4412326A (en) Collision avoiding system, apparatus and protocol for a multiple access digital communications system including variable length packets
GB2166328A (en) In-house distribution facility for a broadband communication system
US4850047A (en) Optical bus communication system utilizing frame format signals
JP2836592B2 (ja) 光送受信器およびその光送受信器を用いたネットワーク
US4646361A (en) Optical star repeater
EP0181346A1 (de) Hochgeschwindigkeits-übertrager für digitale schleife
CA1145417A (en) Active t-coupler for fiber optic local networks which permits collision detection
EP0118763A2 (de) Verfahren zur Fehlerortung in einer digitalen Übertragungsleitung
EP0748077A2 (de) Übertragungssystem mit asymmetrischem Pingpong-Verfahren
GB2128058A (en) Multiple access data communication system
CA1204844A (en) Method and system for controlling the interconnecting of a plurality of local data networks
JPH07202891A (ja) 無線通信ローカルエリアネットワーク
EP0476444A1 (de) Optischer Sender/Empfänger
EP0112126A2 (de) Fernmeldenetz und Verfahren für seine Anwendung
US20060114824A1 (en) Multiple device communications
US4683471A (en) Data bus pilot tone
JPH0214823B2 (de)
JP3068125B2 (ja) バス型光伝送路用通信局
KR920007747Y1 (ko) Lan 접속용 송수신 장치
JPS6198041A (ja) 光トランシ−バ
JPH0410266B2 (de)
JPH0685796A (ja) 二線式伝送システム

Legal Events

Date Code Title Description
AS Assignment

Owner name: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KUROBE, AKIO;NAKATSU, HIROMASA;IKEZAKI, MASAO;AND OTHERS;REEL/FRAME:005210/0981

Effective date: 19900118

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19990903

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362